/*
* Copyright (c) 2013-2016, The PurpleI2P Project
*
* This file is part of Purple i2pd project and licensed under BSD3
*
* See full license text in LICENSE file at top of project tree
*/

#ifndef HTTP_H__
#define HTTP_H__

#include <cstring>
#include <map>
#include <list>
#include <sstream>
#include <string>
#include <vector>

namespace i2p
{
namespace http
{
  const char CRLF[] = "\r\n";         /**< HTTP line terminator */
  const char HTTP_EOH[] = "\r\n\r\n"; /**< HTTP end-of-headers mark */
  extern const std::vector<std::string> HTTP_METHODS;  /**< list of valid HTTP methods */
  extern const std::vector<std::string> HTTP_VERSIONS; /**< list of valid HTTP versions */

  struct URL
  {
    std::string schema;
    std::string user;
    std::string pass;
    std::string host;
    unsigned short int port;
    std::string path;
    std::string query;
    std::string frag;

    URL(): schema(""), user(""), pass(""), host(""), port(0), path(""), query(""), frag("") {};

    /**
     * @brief Tries to parse url from string
     * @return true on success, false on invalid url
     */
    bool parse (const char *str, std::size_t len = 0);
    bool parse (const std::string& url);

    /**
     * @brief Parse query part of url to key/value map
     * @note Honestly, this should be implemented with std::multimap
     */
    bool parse_query(std::map<std::string, std::string> & params);

    /**
     * @brief Serialize URL structure to url
     * @note Returns relative url if schema if empty, absolute url otherwise
     */
    std::string to_string ();

    /**
     * @brief return true if the host is inside i2p
     */
    bool is_i2p() const;
  };

  struct HTTPMsg
  {
    std::map<std::string, std::string> headers;

    void add_header(const char *name, std::string & value, bool replace = false);
    void add_header(const char *name, const char *value, bool replace = false);
    void del_header(const char *name);

    /** @brief Returns declared message length or -1 if unknown */
    long int content_length() const;
  };

  struct HTTPReq
  {
	std::list<std::pair<std::string, std::string> > headers;
    std::string version;
    std::string method;
    std::string uri;

    HTTPReq (): version("HTTP/1.0"), method("GET"), uri("/") {};

    /**
     * @brief Tries to parse HTTP request from string
     * @return -1 on error, 0 on incomplete query, >0 on success
     * @note Positive return value is a size of header
     */
    int parse(const char *buf, size_t len);
    int parse(const std::string& buf);

    /** @brief Serialize HTTP request to string */
    std::string to_string();
		void write(std::ostream & o);

	void AddHeader (const std::string& name, const std::string& value);
	void UpdateHeader (const std::string& name, const std::string& value);
	void RemoveHeader (const std::string& name, const std::string& exempt); // remove all headers starting with name, but exempt
	void RemoveHeader (const std::string& name) { RemoveHeader (name, ""); };
	std::string GetHeader (const std::string& name) const;
  };

  struct HTTPRes : HTTPMsg {
    std::string version;
    std::string status;
    unsigned short int code;
    /**
     * @brief Simplifies response generation
     *
     * If this variable is set, on @a to_string() call:
     *   * Content-Length header will be added if missing,
     *   * contents of @a body will be included in generated response
     */
    std::string body;

    HTTPRes (): version("HTTP/1.1"), status("OK"), code(200) {}

    /**
     * @brief Tries to parse HTTP response from string
     * @return -1 on error, 0 on incomplete query, >0 on success
     * @note Positive return value is a size of header
     */
    int parse(const char *buf, size_t len);
    int parse(const std::string& buf);

    /**
     * @brief Serialize HTTP response to string
     * @note If @a version is set to HTTP/1.1, and Date header is missing,
     *   it will be generated based on current time and added to headers
     * @note If @a body is set and Content-Length header is missing,
     *   this header will be added, based on body's length
     */
    std::string to_string();

		void write(std::ostream & o);

    /** @brief Checks that response declared as chunked data */
    bool is_chunked() const ;

    /** @brief Checks that response contains compressed data */
    bool is_gzipped(bool includingI2PGzip = true) const;
  };

  /**
   * @brief returns HTTP status string by integer code
   * @param code HTTP code [100, 599]
   * @return Immutable string with status
   */
  const char * HTTPCodeToStatus(int code);

  /**
   * @brief Replaces %-encoded characters in string with their values
   * @param data Source string
   * @param null If set to true - decode also %00 sequence, otherwise - skip
   * @return Decoded string
   */
  std::string UrlDecode(const std::string& data, bool null = false);

  /**
   * @brief Merge HTTP response content with Transfer-Encoding: chunked
   * @param in  Input stream
   * @param out Output stream
   * @return true on success, false otherwise
   */
  bool MergeChunkedResponse (std::istream& in, std::ostream& out);
} // http
} // i2p

#endif /* HTTP_H__ */
